| /* Macros for declaring functions as non-returning. |
| |
| Copyright (C) 2017-2020 Free Software Foundation, Inc. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Paul Eggert and Bruno Haible. */ |
| |
| #ifndef _NORETURN_H |
| #define _NORETURN_H 1 |
| |
| /* A "non-returning" function is a function which cannot return normally. |
| It can transfer control only through longjmp(), throw (in C++), or similar |
| mechanisms. |
| |
| This file defines two macros _GL_NORETURN_FUNC and _GL_NORETURN_FUNCPTR, |
| that declare a function to be non-returning. |
| _GL_NORETURN_FUNC is for use in function declarations and function |
| definitions. |
| _GL_NORETURN_FUNCPTR is for use on function pointers. |
| |
| Comparison of this file with <stdnoreturn.h>: |
| <stdnoreturn.h> defines a macro (or keyword) _Noreturn that declares |
| a function to be non-returning. _Noreturn is only for use in function |
| declarations and function definitions. |
| Therefore, if the non-returning functions you have to declare are unlikely |
| to be accessed through function pointers, and if the efficiency with C++ |
| compilers other than g++, clang, MSVC++ is not an issue to you, you can use |
| module 'stdnoreturn' instead of this one, and _Noreturn instead of |
| _GL_NORETURN_FUNC. |
| */ |
| |
| /* Declares that a function is nonreturning. |
| Use in C only code: |
| _GL_NORETURN_FUNC extern void func (void); |
| extern _GL_NORETURN_FUNC void func (void); |
| extern void _GL_NORETURN_FUNC func (void); |
| Use in C++ only code for a function with C linkage: |
| extern "C" { _GL_NORETURN_FUNC void func (void); } |
| Use in C++ only code for a function with C++ linkage: |
| _GL_NORETURN_FUNC extern void func (void); |
| Use in C & C++ code for a function with C linkage: |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| _GL_NORETURN_FUNC void func (void); |
| #ifdef __cplusplus |
| } |
| #endif |
| Use in C & C++ code for a function with current language linkage: |
| _GL_NORETURN_FUNC extern void func (void); |
| */ |
| #if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \ |
| || (0x5110 <= __SUNPRO_C) |
| /* For compatibility with _GL_NORETURN_FUNCPTR on clang, use |
| __attribute__((__noreturn__)), not _Noreturn. */ |
| # define _GL_NORETURN_FUNC __attribute__ ((__noreturn__)) |
| #elif 1200 <= _MSC_VER |
| /* Use MSVC specific syntax. */ |
| # define _GL_NORETURN_FUNC __declspec (noreturn) |
| #elif defined __cplusplus |
| /* Use ISO C++11 syntax when the compiler supports it. */ |
| # if (__cplusplus >= 201103 && !(__GNUC__ == 4 && __GNUC_MINOR__ == 7)) \ |
| || (_MSC_VER >= 1900) |
| # define _GL_NORETURN_FUNC [[noreturn]] |
| /* clang++ supports the _Noreturn keyword, but g++ doesn't. */ |
| # elif defined __clang__ |
| # define _GL_NORETURN_FUNC _Noreturn |
| # else |
| # define _GL_NORETURN_FUNC /* empty */ |
| # endif |
| #else |
| /* Use ISO C11 syntax when the compiler supports it. */ |
| # if __STDC_VERSION__ >= 201112 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7) |
| # define _GL_NORETURN_FUNC _Noreturn |
| # else |
| # define _GL_NORETURN_FUNC /* empty */ |
| # endif |
| #endif |
| |
| /* Declares that a function is nonreturning. |
| Use in types and declarations that involve function pointers: |
| _GL_NORETURN_FUNCPTR void (*funcptr) (void); |
| */ |
| #if (3 <= __GNUC__ || (__GNUC__ == 2 && 8 <= __GNUC_MINOR__)) \ |
| || (0x5110 <= __SUNPRO_C) |
| # define _GL_NORETURN_FUNCPTR __attribute__ ((__noreturn__)) |
| #else |
| # define _GL_NORETURN_FUNCPTR /* empty */ |
| #endif |
| |
| /* Comments about the compiler dependent language features: |
| - '_Noreturn' - standardized by ISO C11, available in C only (not in C++), |
| and not applicable to pointers. |
| - '[[noreturn]]' - standardized by ISO C++11, available in C++ only, |
| and not applicable to pointers. |
| - '__attribute__((__noreturn__))' - available in GCC and clang only, |
| both in C and C++. |
| - '__declspec(noreturn)' - available in MSVC only, |
| both in C and C++, not applicable to pointers. |
| */ |
| |
| #endif /* _NORETURN_H */ |